A Mission Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift to Drag Ratios of Future N+3 Transport Aircraft

Abstract

Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap.

Static Aeroelastic Scaling and Analysis of a Sub-Scale Flexible Wing Wind Tunnel Model

“…The aircraft velocity is (u, v, w) in the aircraft body axes, and (p, q, r) are the aircraft angular velocity components. This can be expressed in the left wing frame D as v v v Q = x t d d d 1 + y t d d d 2 + z t d d d 3 , the local velocity due to aircraft rigid-body dynamics.…”

Static Aeroelastic and Longitudinal Trim Model of Flexible Wing Aircraft Using Finite-Element Vortex-Lattice Coupled Solution

“…These tools can also lead the way to flexible wing design optimization and the development of novel control surfaces to achieve active wing shaping, such as the Variable Camber Continuous Trailing Edge Flap system being investigated in a joint effort by NASA and Boeing. 2,3 …”

Aeroelastic Tailoring of Transport Wings Including Transonic Flutter Constraints

“…The optimization studies in that paper sought to minimize the structural wing mass, subject to stress and panel buckling constraints spread over a set of load cases. A variety of aeroelastic tailoring technologies were considered, including localized shell thickness variations, functionally graded metals (FGM) [2] [3], composite skin laminates, curvilinear tow steered composites [4] [5], and a continuous trailing edge flap [6]. The latter category involves simultaneously optimizing the wing structural details and the scheduling of distributed control surfaces across multiple load cases.…”